Color forming developer and process of color development



Patented Apr. 16, 1940 UNITED STATES PATENT OFFICE No Drawing. Application May 13, 1939, Serial No. 273,560. In Great Britain May 23, 1938 16 Claims.

This invention relates to photographic color development and to processes of color develop-- ment for use in connection with color' photography.

' It-is known that colored photographic images may be formed by using a developer which forms a colored and insoluble oxidation product during development, the colored product thus formed coloring the gelatine adjacent to the silver grains of the silver image. It is also known that a colored image may be formed by adding to certain developer solutions a com-'- pound which couples during development with the oxidation product of the developing agent and forms a coloring substance which is deposited adjacent to the developed silver grains.

Numerous substances have hitherto been employed or proposed to be employed as color couplers among which may be mentioned phenols, naphthols, cr esols,- nitrophenylacetonitriles, aceto-acetic esters. It has not, however, always been possible to select from among those hitherto available one with which the oxidation product of the development agent gives the desired shade with regard to the colors which are already formed or which are bound to be formed in the'other layers. A further limitation in the selection is due to the desirability of using such color couplers which give dyes insoluble in water and resist the efl'ects of the employed photographic baths.

The present invention is based on the discovery of a new group of colorcouplers which in general satisfy the above requirements, and which are hydroxy-derivatives of diphenylmethane or, phenyl-naphthyl-methane, in which both of the aromatic nuclei include at least one hydroxyl group. Such bodies have the following general formula: i

XfCHa-X' where X=Phenyl residue with one hydronl group. in

the ortho or para position with regard to CH2 and where at least two 01' the remaining H-ato'ms in the ring are replaced by two halogen atoms- (C1 or Br). X'=Phenyl or naphthyl residue with; one bydroxyl group in the ortho or para position with regard to CH1, the remaining neatoms of the phenyl or naphthyl residue 'can be substituted or not by halogens, alkyl-, aryl-, or .aralkyl-groups, alkoxy, amino, or nitrogroups and in the case ofa phenyl residue or the ring of a n'aphthyl-reaidue, which ring contains already an OH-groupin the para-position to the OH: group, one or more otthe remainingH-atomsmaybesubsti the corresponding number of OH These color couplers form in general blue or blue-green colors on coupling with the oxidation product of aromatic. amino developing agents during the development of the latent image.

The present invention consists in new or imaddition to an aromatic amino-developing agent a color coupler as above defined. The present invention also includes a new or improved process or method of color development which,comprises developing a latent photographic image by means of an aromatic amino-developer, in the presence of a color coupler as above defined, the silver image which is formed during development being eliminated so that a clear and transparent color image remains.

- The present invention further. includes photographic elements having at least one layer containing a clear transparent image composed essentially of the product resultingfrom the coupling in situ during development of a color coupler as above defined with the oxidation product of an aromatic amino developing agent.

Typical example& 015-: suitable couplers within the scope of the invention are:

(1) 4-(2hydroxy-3',5"- dibromobenzyl) -6-brom- (2) 4 -('2'hydrom-3',5-dibromobenzyl) -a-naphthol: v

. on Y MGM-E (3) 4 (4'hydroxy-3',5'-dibromobenzyl) metacresol: w l

(4) 41- (2hydroxy 3',5"- dibromobenzyl) --amethyl-6-isopropyl phenol:

() 4 (2'hydroxy- 3',5'-dibromobenzyl) 3- methyl-G-bromophenol on em I 5 J a OHQOH (6) 4-(2'hydroxy-3',5'-dibromobenzyD- 1,3 11

hydroxy benzene:

OH OH (7) 4-(2'hydroxy-3',5'-dibromobenzyi) -2 methoxy-phenol:

or: a: cBQoH cm (8) 4-(2hydroxy-3',5-dibromobenzyl)-3 methyl phenol:

,0 on em 35 (9) 4- (2hydroxy-3fl5' dichlorobenzyl) -3 methyl phenol:

OH on.

(1012 (2fhydroxy s',5' dichlorobenzyl) --1- methyl-o-bromophenolz 0H The aromatic amino compounds which may be used as developing agents in the present invention include the mono-d1 and tri-amino aryl compounds. Among the mono-amino developing agents may be mentioned amino-phenols and amino-cresols and their halogen derivatives and amino-naphthols. a A

Thedevelopin'a agents mostly used and giving 90 thebeetresultsin connectionwiththepresent invention are the aromaticortho and para diamines, suchas para-phenylenediamineand its substitution products. These developing agents may be substituted in one amino group or 'in thee5 ring orin-both, iorming compo mds such as:-

,Diethyl phenyienediamine nm hyl ma nh nylenediamine v hyl para phenylenediamiiie 70 3 amino-8 dimethylamino These .compounds are usually kept in the salt form such as hydrochloride -or sulphate. The iollowing developer solutions may be used togiveacoloredhnageaccordingtothenr s nt inventim: I

Formula 1 (A) Para-phenylenediamine HCl -8- 3 Sodium sulphite g 10 Sodium carbonate -..g Sodium hydroxide g 2 5 Water 00m 1000 For use, 3 is added to A. Organic solvents for instance acetone or the like may be used to dissolve the color coupler.

The invention is in no way limited to the use of the color coupler in the developing solution itself. One 01! the essential products the color coupler which, during the development form the dye, can also be added to the photographic emulsion (for instance by absorption upon the silver 30 salts) before or after coating. The other ingredients or the color forming baths, containing chiefly the aromatic amino developing agent, may be applied later, during the developing process, as

a bath. as The present invention may be utilized in the formation of colored photographic images on 7 plates or papers as well as on film employing gelatine or other carrier for the silver halide. The

developing process may be used for the develop- 4 .ing of photographic material, provided with one or more light sensitive layers, which are applied on one side or on both sides or the support.

The silver formed during the developing procas may be eliminated. For this purpose a bath must be used, however, which does not destroy the dye. A bath consisting of a solution in water of potassium ierricyanide and sodium thiosulphate easily eliminates the silver without destroying the dye, leaving a pure dye image.

The newcolor couplers have decided advantages when compared with those known hitherto. They can be produced easily and they form with paradiamino developers blue and blue/green dyes which are practically insoluble in water and in photographic baths. Their principal and most surprising quality is that their capacity of absorption is very small in the blue and'blue/green part of the visible spectrum. They have, turthermore, the interesting property that, it added 0 direct to the developing bath without being previously dissolved in organic solvents, they give intense coloration.

We claim:

1. Color forming developer comprising an am- 5 matic amine developing agent and a color coupler consisting of a diaryl methane having following general formula:

Y x-CH:-.-x-' where =a phenyl residue'with one hydroxyl group in a position other than the meta position with regard to CH2 and where at least two of the remaining H-atoms in the ring' are replaced by twohalogen atoms ll X=an ar'yl residue with one hydroxyl group in a position other than the meta position with regard to CH2. 2. Color forming developer comprising an arci matic amine developing agent and a color coupler consisting of a diaryl methane having the following general formula:

x-cm-x' 10 where a matic amine developing agent and a color coupler consisting of a diaryl methane having the following general formula:

25' XCH:X'

where Y =a phenyl residue with one hydroxyl group in" a position other than the meta position with regard to CH2 and where at least two of the remaining I-I-atoms in the ring are replaced by two halogen atoms X'=a naphthyl residue with one hydroxyl group in a position other than 88- with regard to CH2.

4. Color forming developer comprising an aro- I matic amine developing agent and a color coupler consisting of a diaryl methane havinglthe 4 following general formula;

-X+CHaX' where 1 5. Color forming developercomprising an aromatic amine developing agent and a color coupler consisting of a diaryl methane having the 6 following general formula:

x-orn-x' where X=a phenylresidue with one group a position other than the meta position with regard and where at least two of the remainingH-atomsintheringarereplaced.

by two halogen-atoms X'=a phenyl residue with one hydroxyl group I 70 in a position para with regard to'CH: and at least one of the remaining H-atoms of the residue substituted byan OH group'.

6. Color forming developer comprising an arc- 7 matic amine developing agent and a color'coupler position the meta position where consisting of a diaryl methane having the following general formula:

x-cHz-x' where X=a phenyl residue with one hydroxylgroup in a position other than the meta position with regard to CH2 and where at least two of the remaining H-atoms in the ring are replaced by two bromine atoms 1o X'=an aryl residue with one hydroxyl group in a position other than the meta position with regard to CH2.

7. Color forming developer comprising an aromatic amine developing agent and a color coupler consisting of a diaryl methane having the following. general formula;

XCH2X' where =a phenyl residue with one hydroxyl group in a position other than the meta position with regard to CH2 and where at least two of the remaining H-atoms in the ring are replaced by two bromine atoms I X'=a phenyl residue with one hydroxyl group in a position para with regard to CH2 and at least one of the remaining H-atoms of the residue substituted by an OH group. 8. Color forming developer comprisingan aromatic amine developing agent which is a compound of the aromatic diamine group and a color coupler consisting of a diaryl methane having the following general formula:

where X=a phenyl residue with one hydroxyl group in a position other than the meta position with regard to CH2 and where at least two of the remaining'H-atoms inthe ring are re- 0 placed by two halogen atoms X'=an aryl residue with one hydroxyl group in a position other than the meta position with regard to CH2.

9. Color forming developer comprising an aro- 4 matic amine developing agent which is a substituted phenylene diamine, and a, color coupler consisting of a diaryl methane having the following general formula:

XCHe-'X' where Y X=a phenyl residue with one' hydroxyl group in a position other-than the meta position with regard to CH2 and where at least two of the regard to CH2.

e 10. The process of color development of photographic material containing a developable silver salt image which comprises subjecting the image- I to the action of a color forming developer containing an aromatic amine developing agent and a color coupler consisting of a diaryl methane having the following general formula:

' X-CHa-X' X=a phenyl residue with one hydroxyl group in a position other than the meta position with regard to CH2 and where at least two 'of the remaining'H-atoms in the ring are replaced by two halogenatoms 15- x-crnhx'. as-

a position other than the meta position with regard to CH2. g

11. The process of color development of photographic material containing a developable silver salt image which comprises subjecting the image to the action of a'color forming developer containing an aromatic amine developing agent and a color coupler consisting of a diaryi'methane having the following general formula:

where =a phenyl residue with one hydroxyl groupin a position other than the meta position with regard to CH2 and where at least two of theremaining H-atoms in the ring are replaced by two halogen atoms X'=a phenyl residue with one hydroxyl group in a position other than the meta. position with regard to CH2.

12. The process of color development of photographic material containing a developable silver salt image which comprises subjecting the image to the action of a color forming developer containing an aromatic amine developing agent and a color coupler consisting of a diaryl methane having the following general formula:

X=a phenyl residue with one hydroxyl group in a position other than the meta position with regard to CH3 and where at least two of the X=a phenyl residue with one hydroxyl group in a position other than the meta position with regard to CH2 and where at least two of the remaining H-atoms in the ring are replaced by two halogen atoms X'=an aryl residue with one hydroxyl group in a position other than the meta position with regard to CH2 andat least one H -atom of the residue substituted by an individual included in the group alkyl aryl aralkyl alkoxy amino or nitro halogens and hydroxyl.

- 2,197,311 X'=an aryl residue with one hydroxyl group in 14. The process of color development of photographic material containing a developable silver salt image which comprises subjecting the image I to the action of a color forming developer containing an aromatic amine developing agent and a color coupler consisting of a'diaryl methane having the following general formula:

x=a phenyl residue with one hydroxyl group in a position other than the meta'posltion with regard to CH2 and where at least two of the remaining H-atoms in the ring are replaced by two halogen atoms X'=a phenyl residue with one hydroxyl group in a position para with regard to CH2 and at least one of the remaining H-atomsof the residue substituted by .an' OH group.

15. The process of color development of photographic material containing a developable silver salt image which comprises subjecting the image to the action of a color forming developer containing an aromatic amine developing agent and a color coupler consisting of a diaryl methane having the following general formula:

where.-

X=a phenyl residue with one hydroxyl group in a position other than the meta position with regard to CH2 and where at least two of the remaining H-atoms in the ring are replaced by two bromine atoms X'=an aryl residue with one hydroiqrl group in a position other than the meta position to the action of a color forming developer containing an aromatic amine developing agent and a color coupler consisting of a diaryl methane haviiig the following general formula:

XCH=X' where =a phenyl residue with one hydroxyl group in a position other than the meta position with regard to CH2 and where at least two of the remaining H-atoms in the ring are replaced by two bromine atoms X'=a phenyl residue with one hydroxyl group in a position para with regard to CH2 and at least one of the remaining H-atoms of the residue substituted by an OH group.

PH. 1. J. R. MERCKX. W. K. A. K6RBER. 

